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How To Fix a Dent In a Car


You don't have to be an auto body specialist to know how to fix dings and dents in your car. Most small damage can be easily repaired with simple tools and a little know-how.

Start by assessing the damage. Does it have "crinkles" or sharp points where the metal or plastic has been pinched? This is common in collision dents where either car was moving at more than parking lot speeds or the contact point of the car doing the damage was a sharp corner or edge.

If this is the case, then you'll probably have to replace the dented part or take it to a body shop where they have the right tools to straighten it out.

Most of the time, though, dents are fairly superficial. Assuming no plastic or fiberglass damage, simple dents can be removed using tools you probably have lying around your house or can purchase for just a few dollars.

Hairdryer and CO2 Sprayer

Most people own a hairdryer and have CO2 canisters for cleaning electronics. When the CO2 sprayer is held upside-down, it emits liquid carbon dioxide, which is very cold. The can will have warnings about this. So be careful with it.

The idea here is to give a hot-cold treatment to your car's dent and cause the metals to expand and contract quickly, thus springing back into their intended shape.

First, using the hair dryer, heat up the area in and around the dent for about a minute (or more if it's cold outside). You don't want to overdo it or you may cause the paint to flake, though this will likely take a lot more than a couple of minutes with the dyer.

Once the area is heated up, immediately use the upside-down CO2 can to spray it with liquid carbon dioxide. Do this for about thirty seconds. It will leave an icy-looking film on the dent.

Now wait for a few seconds. As the area warms back up, you'll hear popping sounds as the metal re-aligns itself to its original shape. Wipe the CO2 residue off and the dent should be gone! If it's not entirely gone, wait about ten minutes and then re-apply the above procedure.

Dry Ice

If you live in a hot climate, dry ice will also work. Park the car in the sun so that the surface gets hot. Then (wearing dry ice gloves or using tongs!) rub the area in and around the dent with dry ice. After a minute or two, it will begin to pop and ding, as above.

Rubber Mallet

If the dent is on an area accessible from the opposing side (such as in fenders, trunk quarter panels, or doors), remove all the obstacles you can and get clear access to the dent. Then, using a rubber mallet, gently tap the back side of the dent and attempt to knock it back into place.

If it's too hard to get a hammer in to swing it, place a 2x4 board end over the back side of the dent and hit it with the hammer.

In both cases, begin gently and get more powerful with each stroke until you hit the right amount of force to push out the dent without creating a new one. This works especially well on older vehicles made of sheet metal or steel.

More Advanced Techniques

Finally, some dents just require more work. In these cases, if you're familiar with filler/adhesive (Bondo), dent plungers, and the like, you can use those. Otherwise, you'll probably need to find a qualified body mechanic.

photo by John Nyboer

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